System for combining flow from compressor bleeds of an industrial gas turbine for gas turbine performance optimization

Abstract

A gas turbine cooling and sealing air supply system design for an industrial gas turbine is provided which effectively eliminates the need to dissipate bleed pressure across an orifice or similar device, thereby to optimize full load ISO performance. This flow system is realized by providing cross over valves/ejectors which allow mixing of extractions of different pressures. Control valves provided in the various extraction and cross over flow paths selectively control and determine the flow of extraction bleed air from the various stages of the compressor and between the extraction flow paths. Once the air is combined, its combined pressure and temperature is somewhere between the lower and higher pressure extraction air original pressures and temperatures. Thus, the proper pressure can be supplied to, e.g., the turbine with the least expensive, in terms of work invested, mixture of air with the lowest temperature.

What is claimed is:  
     
       1. A system for bleeding air from plural ports in a multi-stage compressor to provide cooling and/or sealing air to an associated turbine for optimizing gas turbine performance, comprising: 
       a first casing portion surrounding a lower pressure stage of the compressor, said first casing portion having at least one bleed aperture defined therethrough;  
       a first extraction flow path for conducting bleed air from said first casing portion to the turbine;  
       a second casing portion surrounding a mid pressure stage of the compressor, said second casing portion having at least one bleed aperture defined therethrough;  
       a second extraction flow path for conducting bleed air from said second casing portion to the turbine;  
       a first cross over flow path interconnecting said first extraction flow path and said second extraction flow path for selective cross over flow therebetween;  
       a first control valve provided in said first extraction flow path, upstream of said first cross over path;  
       a second control valve provided in said second extraction flow path, upstream of said first cross over path;  
       a first cross over control valve provided in said first cross over flow path for selectively controlling flow between said first extraction flow path and said second extraction flow path; and  
       an ejector in flow communication with said first cross over flow path and said second extraction flow path, at a junction therebetween,  
       whereby flow through and between said first and second extraction flow paths can be selectively controlled to supply air to the turbine at a proper pressure with an economic mixture of bleed air, so that the lower pressure, first extraction flow path can be communicated to a target portion of the turbine at a higher pressure than said low pressure extraction.  
     
     
       2. A system for bleeding air as in  claim 1 , further comprising a third, high-pressure extraction flow path for conducting high pressure bleed air from a compressor discharge extraction manifold to the turbine. 
     
     
       3. A system for bleeding air as in  claim 2 , further comprising a second cross over flow path defined between said second extraction flow path and said third extraction flow path, and a second cross over control valve provided in said second cross over flow path for selectively controlling flow between said third extraction flow path and said second extraction flow path. 
     
     
       4. A system for bleeding air as in  claim 3 , wherein said second extraction flow path includes first and second parallel flow paths, said first parallel flow path being in selective flow communication with said first extraction flow path via said first cross over flow path, said third extraction flow path being in selective flow communication with said second parallel flow path via said second cross over flow path. 
     
     
       5. A system for bleeding air as in  claim 4 , wherein said third extraction flow path includes third and fourth parallel flow paths, said third parallel flow path being in selective flow communication with said second extraction flow path via said second cross over flow path. 
     
     
       6. A system as in  claim 3 , further comprising an ejector in flow communication with said second cross over flow path and said third extraction flow path, at a junction therebetween. 
     
     
       7. A system as in  claim 4 , further comprising an ejector in flow communication with said second cross over flow path and said third extraction flow path, at a junction therebetween. 
     
     
       8. A system for bleeding air as in  claim 1 , wherein said second extraction flow path includes first and second parallel flow paths, said first parallel flow path being in selective flow communication with said first extraction flow path via said first cross over flow path. 
     
     
       9. A method for bleeding air from plural ports in a multi-stage compressor to provide cooling and/or sealing air to an associated turbine for optimizing gas turbine performance comprising: 
       selectively extracting bleed air from a lower pressure stage of the compressor and flowing said low pressure extraction through a first extraction flow path from said lower pressure stage of said compressor toward a first target portion of said turbine;  
       selectively extracting mid pressure bleed air from a mid pressure stage of compressor and selectively flowing said mid pressure bleed air along a second extraction flow path from said mid pressure stage of said compressor toward a second target portion of said turbine; and  
       selectively communicating said first extraction flow path and said second extraction flow path through a first cross over flow path via an ejector in flow communication with said first cross over flow path and said second extraction flow path at a junction therebetween, so as to selectively mix air flowing through said second and first extraction flow paths to control pressure of air supplied to at least one of said target portions of said turbine, so that the lower pressure, first extraction flow path can be communicated to a said target portion at a higher pressure than said low pressure extraction.  
     
     
       10. A method for bleeding air as in  claim 9 , further comprising selectively extracting high pressure bleed air from a high pressure section of the compressor and flowing said high pressure bleed air along a third extraction flow path from said high pressure section of said compressor toward a third target portion of said turbine. 
     
     
       11. A method for bleeding air as in  claim 10 , further comprising selectively communicating said third extraction flow path and said second extraction flow path through a second cross over flow path so as to selectively mix air flowing through said third and second extraction flow paths to control pressure of air supplied to at least one of said target portions of said turbine. 
     
     
       12. A method for bleeding air as in  claim 11 , further comprising splitting said flow in said second extraction flow path for selective flow through one of at least first and second parallel flow paths, said first parallel flow path being in selective flow communication with said first extraction flow path via said first cross over path and said third extraction flow path being in selective flow communication with said second parallel flow path via said second cross over path. 
     
     
       13. A method for bleeding air as in  claim 12 , further comprising splitting said flow in said third extraction flow path for selective flow through one of at least third and fourth parallel flow paths, said third parallel flow path being in selective flow communication with said second extraction flow path via said second cross over path. 
     
     
       14. A method for bleeding air as in  claim 9 , further comprising splitting said flow in said second extraction flow path for selective flow through one of at least first and second parallel flow paths, said first parallel flow path being in selective flow communication with said first extraction flow path via said first cross over path. 
     
     
       15. A system for bleeding air from plural ports in a multi-stage compressor to provide cooling and/or sealing air to an associated turbine for optimizing gas turbine performance, comprising: 
       a first casing portion surrounding a lower pressure stage of the compressor, said first casing portion having at least one bleed aperture defined therethrough;  
       a first extraction flow path for conducting bleed air from said first casing portion to the turbine;  
       a second casing portion surrounding a mid pressure stage of the compressor, said second casing portion having at least one bleed aperture defined therethrough;  
       a second extraction flow path for conducting bleed air from said second casing portion to the turbine;  
       a first cross over flow path interconnecting said first extraction flow path and said second extraction flow path for selective cross over flow therebetween;  
       a first control valve provided in said first extraction flow path, upstream of said first cross over path;  
       a second control valve provided in said second extraction flow path, upstream of said first cross over path;  
       a first cross over control valve provided in said first cross over flow path for selectively controlling flow between said first extraction flow path and said second extraction flow path, whereby flow through and between said first and second extraction flow paths can be selectively controlled to supply air to the turbine at a proper pressure with an economic mixture of bleed air;  
       a third, high-pressure extraction flow path for conducting high pressure bleed air from a compressor discharge extraction manifold to the turbine; and  
       a second cross over flow path defined between said second extraction flow path and said third extraction flow path, and a second cross over control valve provided in said second cross over flow path for selectively controlling flow between said third extraction flow path and said second extraction flow path,  
       wherein said second extraction flow path includes first and second parallel flow paths, said first parallel flow path being in selective flow communication with said first extraction flow path via said first cross over flow path, said third extraction flow path being in selective flow communication with said second parallel flow path via said second cross over flow path, and  
       wherein said third extraction flow path includes first and second parallel flow paths, said first flow path of said third extraction flow path being in selective flow communication with said second parallel flow path of said second extraction flow path via said second cross over flow path.  
     
     
       16. A method for bleeding air from plural ports in a multi-stage compressor to provide cooling and/or sealing air to an associated turbine for optimizing gas turbine performance comprising: 
       selectively extracting bleed air from a lower pressure stage of the compressor and flowing said low pressure extraction through a first extraction flow path from said lower pressure stage of said compressor toward a first target portion of said turbine;  
       selectively extracting mid pressure bleed air from a mid pressure stage of compressor and selectively flowing said mid pressure bleed air along a second extraction flow path from said mid pressure stage of said compressor toward a second target portion of said turbine;  
       selectively communicating said first extraction flow path and said second extraction flow path through a first cross over flow path so as to selectively mix air flowing through said second and first extraction flow paths to control pressure of air supplied to at least one of said target portions of said turbine;  
       selectively extracting high pressure bleed air from a high pressure section of the compressor and flowing said high pressure bleed air along a third extraction flow path from said high pressure section of said compressor toward a third target portion of said turbine;  
       selectively communicating said third extraction flow path and said second extraction flow path through a second cross over flow path so as to selectively mix air flowing through said third and second extraction flow paths to control pressure of air supplied to at least one of said target portions of said turbine; and  
       splitting said flow in said second extraction flow path for selective flow through one of at least first and second parallel flow paths, said first parallel flow path being in selective flow communication with said first extraction flow path via said first cross over path and said third extraction flow path being in selective flow communication with said second parallel flow path of said second parallel flow path via said second cross over path;  
       splitting said flow in said third extraction flow path for selective flow through one of at least first and second parallel flow paths, said first parallel flow path of said third extraction flow path being in selective flow communication with said second extraction flow path via said second cross over path.